1. Field of the Invention
The present invention relates to a method of and an apparatus for manufacturing a slide fastener with a separable end stop of the type in which stringers of continuous length which have space portions disposed at regular intervals in their longitudinal directions are intermittently conveyed and, during a suspension of the conveying operation, upper stops and pins which constitute a separable end stop are formed at each of the space portions by injection molding.
2. Description of the Prior Art
A method and an apparatus of this kind have heretofore been known in which a pair of engaged fastener stringers are separated while being conveyed, and each of the space portions of the stringers separated is stopped at an injection molding station where upper stops and pins which constitute a separable end stop, that is, a removable pin and a box pin, are simultaneously formed by injection molding at the opposite ends of the space portion. Such a method and apparatus have been disclosed in, for example, the specifications of Japanese Patent Laid-Open No. 90345/ 1977 (Laid-Open Date: July 29, 1977) and German Pat. Laid-Open No. 2,709,479 (Laid-Open Date: September 22, 1977). According to this known method and apparatus, errors in positioning the space portion directly lead to positional errors of the upper stops and the pins. Further, even if the position of the space portion is accurately regulated, the following problem still remains. The space portions per se involve variations in length and the degree of elongation of the tape which constitutes each of the stringers differs depending upon the force applied thereto and, therefore, all of these factors have a great effect on the potential for positional errors occurring with the upper stops and the pins. Furthermore, since the upper stops and the pins are simultaneously formed by injection molding, there is a need to employ an undesirably long runner for supplying a molten resin into cavities when forming the upper stops and the pins. This is uneconomical since an unnecessarily large amount of the resin is accordingly used. In addition, it is unfavorably necessary for dies of disadvantageously increased size to be used for the injection molding.